1. Field of the Invention
The present invention relates to an image pick up device for use in a mobile camera or the like. More particularly, the present invention relates to a CMOS type image sensor module including a semiconductor chip having a CMOS-based sensor for picking up an image, and a built-in digital signal processing semiconductor chip.
2. Description of the Related Art
An image sensor module of a camera is a multi-chip device that includes an image sensing semiconductor chip and a digital signal processing semiconductor chip. The image sensing semiconductor chip collects optical images, and the digital signal processing semiconductor chip converts the optical images into electrical signals. Based on the particular type of semiconductor used, the image sensor modules are classified as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) device.
A CMOS type of image sensor module is disclosed in U.S. Pat. Application No. 2003-0025825, entitled “Small Image Pickup Module” filed on Aug. 29, 2002 by Olympus Optical Co., Ltd.
FIG. 1 is a cross-sectional view of the disclosed CMOS type of image sensor module. Referring to this figure, the CMOS type image sensor module has an image sensing semiconductor chip 12 and a digital signal processing semiconductor chip 18 which are mounted horizontally on a substrate 11 as spaced laterally from one another. In addition, a discrete lens kit 13 is connected to the substrate 11 by potting material 271 and 272 that also serves to create a seal between the lens kit 13 and substrate 11. The image sensing semiconductor chip 12 is protected by a transparent cover 25. The cover 25 and image sensing semiconductor chip 12 are secured to one another and to the substrate 11 by potting material 261 and 262. The digital signal processing semiconductor 18 is sealed by a syringe-type of potting material. Reference numbers 14, 15, and 16 designate an infrared filter, an optical lens, and a diaphragm, respectively.
However, the above-described CMOS type of image sensor module has disadvantages.
First, the manufacturing of the CMOS type of image sensor module is a complicated process entailing a high production cost because it involves creating a seal between the lens kit 13 and the substrate 11. Moreover, the image sensing semiconductor chip 12 and the digital signal processing semiconductor chip 18 are molded to the substrate 11 through separate processes.
Second, the difficulties and complexity of the manufacturing process, especially when adapted for mass production of the CMOS type of image sensor module, lead to frequent manufacturing defects. That is, the prior art CMOS type of image sensor module is manufactured with a relatively low productivity.
Third, the prior art CMOS type of image sensor module is relatively large because the image sensing semiconductor chip and the digital signal processing semiconductor chip are mounted to the substrate horizontally as spaced laterally from each other.